A steel tube is pushed through a die that grips the tube. A mandrel is then forced into the end of the tube, flaring the tube by means of a cold working process. Thus the term flaring refers to the increasing of the diameter of a certain part of a tube.

Flaring is mostly used during the manufacturing of lancing tubes. These tubes are flared to fit themselves to provide a continuous production. Lancing tubes are also manufactured as an open lance and wire packed.